Medical researchers have known for many years that diseases can be detected by biomarkers in the breath. See, e.g., Buszewski et al., Bioanalysis 5(18):2287-2306 (2013). In one application of this knowledge, researchers have trained dogs to smell for cancer. See, e.g., McCulloch et al., Integrative Cancer Therapies 5(1):30-39 (2006). The range of diseases that have been detected by smell are lung cancer, Parkinson's, prostate cancer, breast cancer, colon cancer, small intestine bacterial overgrowth, and asthma.
When patients breathe in and out, they release volatile organic molecules that are biomarkers for particular diseases. Changes in the concentration of the biomarkers can be used to identify the disease. These biomarkers are often in very low concentrations, ranging from a few parts per million to under one part per billion.
VOCs make up the majority of the scents and smells human and animals can sense. While smell has not been formally used in routine medical practice in recent times, there are well known scents associated with particular conditions. For example, the smell of death is created by VOCs, in particular putrescine and cadaverine, which are released when cells die. Other VOCs, such as ketones, are exhaled if there is not enough insulin to help the body use sugar for energy. Lung cancer has over 40 known VOCs that researches have shown can indicate lung cancer.
A major challenge in measuring the VOCs in breath is the complexity of the sample. There are over 1,000 known compounds in breath. Trying to separate and measure all these compounds has been a logistical challenge for makers of devices. Simple devices often can only measure a class of compounds, or have unknown specificity and selectivity towards different VOCs.
Devices used in research have suffered from being very complex to use, making them difficult to deploy in a standard clinical environment, or they have been to very expensive to use making them unattractive for a screening test. It is therefore appreciated there is a need in the art for a small and inexpensive device that can be used to measure biomarkers in the breath.